Surgical needle-suture attachment

ABSTRACT

A combined surgical needle-suture device of controlled suture release characteristics and a method for manufacturing the device employ a shrinkable tubing and a suture having an expandable tip region to connect the needle to the suture.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of commonly assigned,copending U.S. patent application Ser. No. 413,240, filed Sept. 27, 1989now pending.

BACKGROUND OF THE INVENTION

The present invention relates to a method for attaching a surgicalneedle to a suture to provide a combined surgical needle-suture deviceand, more particularly, to such a method in which a shrinkable tubing isemployed to secure the needle to the suture.

For many years, surgeons have employed needle-suture combinations inwhich a suture or ligature is attached to the shank end of a needle.Such needle-suture combinations are provided for a wide variety ofmonofilament and braided suture materials, both absorbable andnonabsorbable, e.g., catgut, silk, nylon, polyester, polypropylene,linen, cotton, and absorbable synthetic materials such as polymers andcopolymers of glycolic and lactic acids.

Needle-suture combinations fall into two general classes: standardneedle attachment and removable or detachable needle attachment. In thecase of standard needle attachment, the suture is securely attached tothe needle and is not intended to be separable therefrom, except bycutting or severing the suture. Removable needle attachment, bycontrast, is such that the needle is separable from the suture inresponse to a force exerted by the surgeon. Minimum acceptable forcesrequired to separate a needle from a suture (for various suture sizes)are set forth in the United States Pharmacopoeia (USP). The UnitedStates Pharmacoooeia prescribes minimum individual pull-out forces andminimum average pull-out forces as measured for five needle-suturecombinations. The minimum pull-out forces for both standard andremovable needle-suture attachment set forth in the United StatesPharmacopoeia are hereby incorporated by reference.

One typical method for securing a suture to a needle involves providinga cylindrical recess in the shank end of a needle and securing a suturetherein. For example, U.S. Pat. No. 1,558,037 teaches the addition of acement material to such a substantially cylindrical recess to secure thesuture therein. Additional methods for bonding a suture within a needlebore are described in U.S. Pat. Nos. 2,928,395 (adhesives) and 3,394,704(bonding agents). Alternatively, a suture may be secured within an axialbore in a needle by swaging the needle in the region of the recess. See,e.g., U.S. Pat. No. 1,250,114. Additional prior art methods for securinga suture within a needle bore include expansion of a catgut suturethrough the application of heat (U.S. Pat. No. 1,665,216), inclusion ofprotruding teeth within the axial bore to grasp an inserted suture (U.S.Pat. No. 1,678,361) and knotting the end of the suture to be insertedwithin the bore to secure the suture therein (U.S. Pat. No. 1,757,129).

Methods for detachably securing a suture to a needle are also wellknown. For example, U.S. Pat. Nos. 3,890,975 and 3,980,177 teach swaginga suture within a needle bore such that the suture has a pull-out valveof 3 to 26 ounces. Alternative detachable attachment methods includeproviding a weakened suture segment (U.S. Pat. No. 3,949,756), lubricanttipping the end of a suture to be inserted in the axial bore of a needle(U.S. Pat. No. 3,963,031) and pre-tensioning a suture that is swagedwithin an axial needle bore (U.S. Pat. No. 3,875,946). See also, U.S.Pat. Nos. 3,799,169; 3,880,167; 3,924,630; 3,926,194; 3,943,933;3,981,307; 4,124,027; and, 4,127,133.

Another method for attaching a suture to a needle involves the use oftubing which is secured to the shank end of the needle and to thesuture. For example, U.S. Pat. No. 1,613,206 describes the use of atubing (preferably silver) which is secured to the shank end of a needleand to a ligature. It is suggested that the tube may be attached to theneedle by pressure or soldering and to the ligature by pressure orcementing. It is also suggested that the shank of the needle be ofreduced cross section and that the furthest extremity of the reduceddiameter shank section be provided with a spike or point upon which thesuture may be secured prior to tube application.

U.S. Pat. No. 2,240,330 describes a tubing attachment method whereby thetubing and suture are releasably secured to the needle. In particular,the needle and tubing are provided with cooperating catch and abutmentmeans which are released one from the other by rotating the needle 90°relative to the tubing (or vice versa). The tubing is manufactured fromspring-tempered carbon steel or chrome nickel steel and is secured tothe suture by heating the tubing and then swaging to the suture.

U.S. Pat. No. 3,311,100 relates to a flexible composite suture having atandem linkage. The needle is secured to a flexible suture leadermanufactured from a readily sterilizable plastic such as nylon, linearpolyethylene, isotactic polypropylene, polyester, silk or otherproteinaceous material, e.g., by inserting and crimping the leaderwithin an axial bore in the needle shank. The opposite end of the sutureleader is crimped within a connector sleeve of a thin walled metaltubing, e.g., stainless steel. The opposite end of the tubing is crimpedaround a stiff suture, e.g., monofilament stainless steel.

U.S. Pat. No. 3,918,455 describes a needle-suture attachment wherein ahollow suture portion is secured to the shank end of a needle which isof reduced cross-section as compared to the remainder of the needle.

Additional patents which describe the use of tubing to effectsuture-needle attachment include U.S. Pat. Nos. 4,672,734 (formingneedle from U-shaped metal plate around suture), 4,359,053 (siliconetubing), 3,835,912 (laser welding of metal tube to needle), 2,814,296,2,802,468 (chamfered tubing ends), 2,302,986, 2,240,330, 1,981,651(needle and tubing screw threaded), 1,960,117, and 1,591,021.

Numerous disadvantages exist with methods used heretofore to effectneedle-suture attachment. For example, those methods which involve theformation and use of an axial bore in the shank end of the needlerequire the use of expensive hole forming equipment. Moreover, it isdifficult to maintain the bore concentric with the center-line of theneedle and to control the depth (and diameter) of the bore when drillingthe needle shank, whether using conventional drilling equipment or laserdrilling. Another disadvantage is the possibility that foreignsubstances may inadvertently or uncontrollably be introduced into theneedle bore, e.g., oil used during drilling or silicone from the needlesilconization process. Safeguards employed in an attempt to prevent theintroduction of such foreign materials, e.g., water blocking duringneedle silconization, are inconvenient adding time, effort and cost tothe needle production process.

Attachment processes which employ bored needle shanks also limit therange of materials from which needles may be fabricated in a costeffective fashion. For example, it is exceedingly difficult to drillSeries 300 stainless steel (laser drilling is required) and, oncedrilled, it is difficult to swage Series 300 stainless steel in aconsistent and reliable manner. For this reason, Series 300 stainlesssteel is not employed for the vast majority of needled suture productsdespite its advantageous combination of strength and ductilitycharacteristics as compared to conventionally employed Series 400stainless steel.

Additional disadvantages associated with needle-suture attachmentmethods which employ bored needle shanks include the weakness impartedto the bored section of the needle, particularly after swaging, and theattendant increased possibility that the needle will fracture in thisregion. It is also difficult to provide a specialized surface finish tothe needle shank to assist in needle attachment, e.g., a texturizedsurface and/or a tapered bore. Swaging equipment used in suchneedle-suture attachment methods is also maintenance intensive.

Needle-suture attachment methods which have employed tubings heretoforealso exhibit numerous disadvantages. Methods which employ metal tubingsgreatly diminish the flexibility of the needle-suture combination in theattachment region. Such diminished flexibility has a deleterious effectin many surgical procedures. Swaging of the tubing to the needle and thesuture is also undesirable in that swaging is time-consuming,maintenance intensive, and subject to variability in attachment force.

Moreover, needle-suture attachment methods which have employed tubingsheretofore have necessarily required the use of tubing having an innerdiameter essentially equal to the outer diameters of the needle shankand suture tip to be attached. Too large a difference between theaforesaid inner and outer diameters inhibits the attachment process, andprevents a tight, secure interface between needle (and/or suture) andtubing. The limited tolerance between the tubing inner diameter and theneedle shank/suture outer diameters in such methods make thesedimensions critical, thereby making the attachment process moredifficult and time-consuming, and increasing the likelihood ofattachment failure and/or rejected materials.

Commonly assigned, copending U.S. patent application Ser. No. 413,240,filed Sept. 27, 1989, of which the present application is acontinuation-in-part, describes and claims a combined surgicalneedle-suture device and surgical needle-suture attachment method whichovercomes the aforementioned drawbacks of the previously knownneedle-suture combinations and needle-suture attachment methods. Inaccordance with said application, a combined surgical needle-suturedevice is provided in which a surgical needle having a shank of reducedcross-section is attached to a suture through a shrinkable tubing, ormicroferrule, which is fitted about the needle shank and a portion ofthe suture. Application of energy to the shrinkable tubing brings thetubing into engagement with both the needle shank and the suture. Thephysical and chemical characteristics of the shrinkable tubing material,the relative diameters of the tubing, the needle shank and the suture,and the amount of energy applied to the tubing may be controlled toprovide a needle-suture combination having a desired pull-out force. Itis thus possible to produce standard needle-suture combinations andremovable needle-suture combinations using a single attachment processand a common inventory of materials.

Minimum average pull-out forces for various sizes of combined surgicalneedle-suture devices are set forth in the United States Pharmacopoeiaand are as follows:

    ______________________________________                                                      Average Pull-Out                                                Suture Size   Force/Ounces                                                    ______________________________________                                        8/0            2.39                                                           7/0            3.20                                                           6/0            5.92                                                           5/0            7.97                                                           4/0           15.97                                                           3/0           23.63                                                           2/0           38.80                                                           1/0           52.89                                                           1             63.48                                                           2 and larger  63.48                                                           ______________________________________                                    

U.S. Pat. No. 3,875,946, referred to supra, describes needle-suturecombinations said to exhibit suture pull-out values that aresubstantially less than those given by the United States Pharmacopoeiaas set forth above. According to U.S. Pat. No. 3,875,946, employing theprocedure described therein, combined surgical needle-suture devices canbe obtained with the following average pull out forces:

    ______________________________________                                                      Average Pull-Out                                                Suture Size   Force/Ounces                                                    ______________________________________                                        8/0           1-2                                                             7/0           1-3                                                             6/0           2-5                                                             5/0           3-7                                                             4/0            3-15                                                           3/0            3-23                                                           2/0            3-26                                                           1/0           10-26                                                           1             10-26                                                           2 and larger  10-26                                                           ______________________________________                                    

These pull-out forces are obtained by prestressing the suture, i.e., byapplying tension to the suture after the tip of the suture has beeninserted into an axial bore, or recess, formed in the blunt end of theneedle and the needled suture has been swaged so that the force requiredto pull the suture out of the recess exceeds the minimum limits onneedle attachment set forth in the United States Pharmacopoeia but isless than the actual tensile strength of the suture used. As the sutureis pulled from the needle during application of the tensioning force,the force required to move the suture relative to the swaged sectiondecreases. When the tensioning force required to move the end of thesuture relative to the needle recess drops to the desired pull-outvalue, the tension is released.

The foregoing procedure is said to permit better control of theresulting needle-suture device in that the force required to separate asuture of a particular size from its attached needle is uniform.

In the approach to achieving controlled needle-suture separationdescribed in aforementioned U.S. Pat. No. 3,981,307, the contents ofwhich are incorporated by reference herein, a suture tip is insertedinto the recess formed in the blunt end of the needle and the needle isthereafter heated to expand the suture tip within the recess into tightengagement with the recess walls. Sutures of synthetic polymers attachedin this manner are removable from the needle recess by application of astraight pulling force of less than about 30 ounces.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a method forattaching a surgical needle to a suture to provide a combined surgicalneedle-suture device which comprises:

a) providing a surgical needle possessing a shank end of reducedcross-section and a suture possessing an expandable tip region;

b) placing a shrinkable tubing around the reduced diameter shank end ofthe needle and the expandable tip region of the suture;

c) shrinking the tubing; and,

d) expanding the tip region of the suture,

the shrinkage of the tubing and the expansion of the tip of the suturecausing engagement of the needle and the suture and resulting in thecombined surgical needle-suture device.

The present invention also provides a needle-suture combination in whichthe needle and suture are joined by a shrinkable tubing and expandablesuture tip. The physical and chemical characteristics of the shrinkabletubing material, the relative diameters of the tubing, the needle shankand the suture, the expansion characteristics of the suture tip and theamount of energy applied to the tubing and suture tip can be controlledto provide a needle-suture combination having a desired pull-out force.It is thus possible to produce standard needle-suture combinations andremovable needle-suture combinations using a single attachment processand a common inventory of materials.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1 is a side cross-sectional view of a needle possessing a shank ofreduced diameter and a suture possessing an expandable tip with ashrinkable tubing positioned around the needle shank and the suture tip(prior to engagement of the tubing with the needle and suture);

FIG. 2 is a side cross-sectional view of the needle and suturecombination of FIG. 1 following shrinking of the tubing and expansion ofthe suture tip to effect engagement of the needle suture; and,

FIG. 3 is a side view of the combined surgical needle-suture device ofFIG. 2;

FIG. 4 is a side view of an alternative embodiment of the presentinvention in which the needle shank is scored;

FIG. 5 is a side view of an alternative embodiment of the presentinvention in which the needle shank is ribbed;

FIG. 6 is a side view of an alternative embodiment of the presentinvention in which the needle shank is threaded;

FIG. 7 is a side view of an alternative embodiment of the presentinvention in which the needle shank is tapered to expand in a directionaway from a remainder of the needle; and

FIG. 8 is a side view of an alternative embodiment of the presentinvention in which the needle shank is tapered to expand in a directiontowards the remainder of the needle.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a combined surgical needle-suturemethod and resulting surgical needle-suture device featuring controlledsuture release. The invention can be used to effect standard ordetachable needle attachment as described in more detail below.

Referring to FIGS. 1-3, needle 10 has a reduced cross-sectional diameterat its shank end 12 relative to the remainder of needle 14. The diameterof shank end 12 can be reduced by any conventional means, e.g., bymachining on a lathe. Typically, shank end 12 has a diameter from 10 to65% smaller than the remainder of the needle 14, and preferably from 25to 50% smaller. It is also possible to provide shank end 12 with atexturized surface to facilitate gripping by shrinkable tubing 20. Forexample, shank end 12 can be scored, ribbed or threaded, in whole or inpart (FIGS. 4-6 respectively). It may also be desirable to taper shankend 12 such that its butt, or distal, end 16 is of greatercross-sectional diameter than the cross-sectional diameter of shank end12 in the region of shoulder 18, or vice versa (FIGS. 7 and 8respectively). Shank end 12 is placed within tubing 20 as shown in FIG.1.

To be suitable herein, suture 30 must be capable of expansion at its tipregion 31. Suitable sutures include those disclosed in U.S. Pat. No.3,981,307, referred to suora, namely, sutures made from a normallycrystalline, oriented synthetic polymer which becomes substantiallydisoriented and amorphous and is expandable at elevated temperature. Byapplying heat or other suitable energy to the tip region of a suture ofthis type, the suture will expand in this region to make contact withthe shrinkable tubing, the latter shrinking under the influence of heator other energy source as hereinafter described to increase thecompressive force between the suture tip and the tubing.

Shrinkable tubing 20 can be manufactured from any material whichshrinks, i.e., reduces in diameter, in response to the application ofenergy. Suitable materials include "memory metals," e.g.,nickel-titanium mixtures, nickel-iron-titanium mixtures, or copper basedmaterials, as are well known in the art (see, e.g., U.S. Pat. Nos.3,759,552, 3,801,954, 4,198,081, and 4,773,680), and shrinkable plasticmaterials, such as polyvinylidene fluoride materials available fromRaychem Corporation, Menlo Park, Calif., under the tradename Kynar. Inthe case of shrinkable plastic materials, the tubing is typicallyextruded such that the inner diameter is less than the final desiredinner diameter, i.e., the inner diameter of the tubing after energyapplication in the attachment method of the present invention.Thereafter, the extruded tubing is expanded radially outward throughradial expansion means to provide a tubing of expanded inner diameter asshown, for example, by tubing 20 in FIG. 1. Such plastic tubing is thusadapted to shrink, or "recover", to its original extruded inner diameterin response to the application of a predetermined amount of energy.

Suture 30 is positioned within shrinkable tubing 20 with expandablesuture tip 31 abutting or separated a short distance from distal end 16of shank 12. As shown in FIG. 1, suture 30 can initially be of uniformcross-section throughout its length. The expandable tip region 31 ofsuture 30, i.e., the region inserted into tubing 20, can be of reducedcross-section relative to the remaining portion 32 of suture 30, e.g.,by tipping the suture tip with an adhesive or resinous tipping agentwhile suture 30 is under tension. (See, e.g., Canadian Patent No.1,009,532.) Resin tipping may be desirable to prevent brooming of thesuture, particularly for multifilament braided sutures, by rigidifyingthe end of the suture thus facilitating its handling during theattachment process. Reducing the diameter of the suture tip, as bytipping under tension, may be desirable to allow a suture of largerdiameter, e.g., a suture diameter equal to the diameter of the needle towhich it is to be attached, to be more efficiently attached to theneedle using the shrinkable tubing of the present invention. It is notnecessary according to the present invention, however, to reduce thediameter of the expandable tip region of suture 30 to efficiently attachneedle 10 to suture 30. Indeed, it may be possible or desirable to applya tipping agent to prevent brooming without reducing suture diameter. Asshown in FIG. 1, shrinkable tubing 20 initially has an inner diameterthat is larger than the outer diameter of the expandable tip region ofsuture 30, thereby minimizing the importance of suture tipping.

After shrinkable tubing 20 is placed around shank end 12 of needle 10and expandable tip region 31 of suture 30, energy is applied to tubing20 and underlying tip region 31 which causes tubing 20 to shrink and tip31 to expand. The shrinkage of tubing 20 brings its inner surface intoengagement with shank end 12 and suture tip 31 thereby securing suture30 to needle 10. Expansion of tip 31 brings its surface into compressiveengagement with shrinking tubing 20, the two actions, i.e., expansionand shrinkage, combining to provide engagement of the tubing and thesuture.

The amount of energy applied to the tubing to effect the desiredattachment, i.e., shrinkage, depends upon the chemical characteristicsof the tubing material, the relative dimensions of the tubing, the shankend of the needle and the suture and the desired pull-out force for theneedle-suture combination. For example, one polyvinylidene fluoridematerial available from Raychem Corporation (RT-850) shrinks attemperatures greater than 175° C., and is adapted to recover to about50% of its radially expanded inner diameter. In such case, tubing 20 canbe brought into engagement with shank end 12 of needle 10 and tip 31 ofsuture 30, either simultaneously or sequentially, by heating tubing 20to a temperature above 175° C. Tubing 20 can be heated through contactwith a hot gas stream or with heated dies, or by other heating means.Typically, the outer diameters of shank end 12 and suture tip region 31are greater than the fully recovered diameter of tubing 20, e.g.,greater than 50% of the initial inner diameter of tubing 20 for theRT-850 material, such that tubing 20 engages shank end 12 and suture tip31. It is preferred that the attachment conditions be controlled suchthat the tubing remains secured to the needle once the suture isdetached.

One suitable procedure for accomplishing expansion of expandable tipregion 31 is to raise the temperature of this region to a level which isbelow the melting point of the suture material but at whichsubstantially all of the orientation and/or crystallinity of thematerial disappears. Appropriate temperatures for this change will varywith the nature of the material but a suitable temperature for aparticular material can be readily determined by slowly raising thetemperature of a sample of the material while observing changes in itsdimensions and birefringence in a polarizing microscope.

The sutures suitable for needle attachment by the method of the presentinvention include monofilament and braided sutures. As previouslystated, the sutures can be made of any synthetic polymer which is knownto lose substantially all of its orientation and/or crystallinity at atemperature close to, but not as high as, its melting point. Typicalsynthetic polymers of this type include nylon, polypropylene, andpolyesters, such as polyethylene terephthalate, and homopolymers andcopolymers of lactide and glycolide with each other and with othermonomers.

The expansion of suture tip 31 and shrinkage of tubing 20 can beeffected simultaneously, e.g., by application of heat or otherappropriate energy which is sufficient to accomplish both actions at thesame time, or in sequence, e.g., shrinkage of tubing 20 can be achievedby heat energy, radiation, microwave energy, etc., followed by expansionof tip 31 accomplished by application of heat or some other type ofenergy thereto, and vice versa.

The expansion characteristics of suture tip 31 and the shrinkingcharacteristics of tubing 20 can be selected so that in combination, theexpanded suture tip and shrunken tubing provide a gripping force uponreduced shank 12 of needle 10 and suture tip 31 which effects standard,i.e., ordinarily non-detachable, attachment of the needle and suture.Alternatively, such characteristics can be selected so as to provide agripping force upon the needle shank and suture tip which, to effectneedle separation or detachment, can be overcome by an average pull-outforce falling within the following range for the suture size indicated:

    ______________________________________                                                      Average Pull-Out                                                Suture Size   Force/Ounces                                                    ______________________________________                                        8/0           1-2                                                             7/0           1-3                                                             6/0           2-5                                                             5/0           3-7                                                             4/0            3-15                                                           3/0            3-23                                                           2/0            3-26                                                           1/0           10-26                                                           1             10-26                                                           2 and larger  10-26                                                           ______________________________________                                    

As shown in FIGS. 1-2, shrinkable tubing 20 is simultaneously placedaround both suture tip 31 and shank end 12 of needle 10 in oneembodiment of the present invention. It is preferable, however, tosequentially secure tubing 20 to needle 10 and suture tip 31. Thus, in apreferred embodiment of the present invention, shrinkable tubing 20 isinitially secured to shank end 12 through the localized application ofenergy to tubing 20 in the region surrounding shank end 12. After tubing20 has been brought into engagement with shank end 12, tip 31 of suture30 is inserted into tubing 20 and additional energy is applied theretoto simultaneously or sequentially shrink tubing 20 and expand suture tip31 as previously described.

The foregoing surgical needle-suture attachment procedure has manyadvantages over previous attachment methods. Machining of the needle toprovide a reduced diameter needle shank is much easier and morecontrollable than drilling processes, and permits the use of needlealloys which have previously been impractical, e.g., Series 300stainless steel and MP35N (available from SPS Technologies). Theseheretofore impractical alloys have advantageous strength and ductilitycharacteristics as compared to conventionally used Series 400 stainlesssteels. Moreover, an unreliable, expensive and maintenance intensiveswaging process is replaced by a sterile, controllable and relativelyinexpensive energy supply. The tubing used in the present invention maybe color coded to designate suture material, standard versus detachableattachment, etc., particularly where a plastic tubing is employed.

The attachment method is also much more efficient from a processing andinventory control standpoint. For example, the tubing can be removedfrom a needle and the needle attached to a fresh suture as may be thecase where the suture and/or attachment properties of the initialsuture-needle combination are outside specifications. In many instances,the suture can also be recovered and reused thereby greatly reducingprocessing waste. The range of acceptable suture diameters is greatlyexpanded due to the ability of the tubing to recover or shrink tovarying degrees thereby minimizing the likelihood that suture productionwill be rejected for inability to attach several needle sizes becausethe shrinkable tubing is capable of recovering or shrinking to varyingdegrees. This greatly simplifies inventory considerations. Moreover, theneedle-suture combinations are atraumatic and advantageously exhibitflexibility in the attachment region.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the invention,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the invention as defined by the claimsappended hereto.

What is claimed is:
 1. A method for attaching a surgical needle to asuture to provide a combined surgical needle-suture device whichcomprises:a) providing a surgical needle possessing a shank end ofreduced cross-section and a suture possessing an expandable tip region;b) placing a shrinkable tubing around the reduced diameter shank end ofthe needle and the expandable tip region of the suture; c) shrinking thetubing; and, d) expanding the tip region of the suture, the shrinkage ofthe tubing and the expansion of the tip of the suture causing engagementof the needle and the suture and providing the combined surgicalneedle-suture device.
 2. The method of claim 1 providing an ordinarilynon-detachable combined surgical needle-suture device.
 3. The method ofclaim 1 providing a detachable combined surgical needle-suture device.4. The method of claim 3 wherein the shrinkable characteristics of thetubing and the expansion characteristics of the suture tip are such asto provide an average pull-out force falling within the following rangefor the suture size indicated:

    ______________________________________                                                      Average Pull-Out                                                Suture Size   Force/Ounces                                                    ______________________________________                                        8/0           1-2                                                             7/0           1-3                                                             6/0           2-5                                                             5/0           3-7                                                             4/0            3-15                                                           3/0            3-23                                                           2/0            3-26                                                           1/0           10-26                                                           1             10-26                                                           2 and larger  10-26                                                           ______________________________________                                    


5. The method of claim 1 wherein the shrinkable tubing is fabricatedfrom a shrinkable metal or a shrinkable plastic.
 6. The method of claim1 wherein the shrinkable tubing is fabricated from a shrinkablepolyvinylidene fluoride plastic.
 7. The method of claim 1 wherein thesuture is made of a synthetic polymer which loses substantially all ofits orientation and/or crystallinity at a temperature close to, but notas high as, its melting point.
 8. The method of claim 7 wherein thesuture is a monofilament or braided suture fabricated from a materialselected from the group consisting of nylon, polypropylene, polyethyleneterephthalate, lactide homopolymer, glycolide homopolymer, lactidecopolymer and glycolide copolymer.
 9. The method of claim 1 whereinshrinking of the tubing is achieved by application of heat to thetubing.
 10. The method of claim 1 wherein expansion of the suture tip isachieved by application of heat to the suture tip.
 11. The method ofclaim 1 wherein the step of shrinking the tubing further comprisesapplying energy to the tubing to shrink the tubing into engagement withthe needle shank end and thereafter applying energy to the tubing toshrink the tubing into engagement with the expandable tip region of thesuture.
 12. The method of claim 1 wherein shrinking of the tubing andexpanding of the suture tip are carried out simultaneously orsequentially.
 13. A combined surgical needle-suture device whichcomprises:a) a surgical needle possessing a shank of reducedcross-section; b) a suture possessing an expandable tip region; and, c)a shrinkable tubing around the reduced diameter shank end of the needleand the expandable tip region of the suture, the tubing being shrunkaround the reduced diameter shank end of the needle and the expanded tipregion of the suture to provide engagement of the needle and suture. 14.The combined surgical needle-suture device of claim 13 which is anordinarily non-detachable combined surgical needle-suture device. 15.The combined surgical needle-suture device of claim 13 which is adetachable combined surgical needle-suture device.
 16. The combinedsurgical needle-suture device of claim 15 wherein the shrinkablecharacteristics of the tubing and the expansion characteristics of thesuture tip are such as to provide an average pull-out force fallingwithin the following range for the suture size indicated:

    ______________________________________                                                      Average Pull-Out                                                Suture Size   Force/Ounces                                                    ______________________________________                                        8/0           1-2                                                             7/0           1-3                                                             6/0           2-5                                                             5/0           3-7                                                             4/0            3-15                                                           3/0            3-23                                                           2/0            3-26                                                           1/0           10-26                                                           1             10-26                                                           2 and larger  10-26                                                           ______________________________________                                    


17. The combined surgical needle-suture device of claim 13 wherein thesuture is fabricated from a fiber-forming material selected from thegroup consisting of collagen, silk, cotton, linen, nylon, polypropylene,polyethylene terephthalate, lactide homopolymer, lactide copolymer,glycolide homopolymer and glycolide copolymer.
 18. The combined surgicalneedle-suture device of claim 13 wherein the shrinkable tubing is amemory metal or shrinkable plastic.
 19. The combined surgicalneedle-suture device of claim 13 wherein the shrinkable tubing is ashrinkable polyvinylidene fluoride material.
 20. The combined surgicalneedle-suture device of claim 13 in which the shank end is provided witha texturized surface to faciliatate gripping by said shrinkable tubing.21. The combined surgical needle-suture device of claim 20 wherein theshank is scored, ribbed or threaded, in whole or in part.
 22. Thecombined surgical needle-suture device of claim 13 wherein said shank ofreduced cross-section forms a shoulder with a remainder of said needle.23. The combined surgical needle-suture device of claim 22 wherein saidshank of reduced cross-section is tapered to expand in a direction awayfrom said shoulder, such that a distal end of said shank is of greatercross-sectional diameter than cross-sectional diameter of said shank ina region of said shoulder.
 24. The combined surgical needle-suturedevice of claim 22 wherein said shank of reduced cross-section istapered to expand in a direction toward said shoulder, such that adistal end of said shank is of smaller cross-sectional diameter thancross-sectional diameter of said shank in a region of said shoulder.